Python Data Science Pandas Data Frames

A Pandas DataFrame is a 2 dimensional data structure, like a 2 dimensional array, or a table with rows and columns.

How to Create A Simple Pandas DataFrame?

Example 1: Create a simple Pandas DataFrame.

Code

import pandas as pd

data = {

'Fruits': ["Mangoes", "Apples","Bananas", "Grapes", "Oranges"],

'Popularity Ranks': [1, 2, 3, 4, 5]

}

#load data into a DataFrame object:

df = pd.DataFrame(data)

print(df)

the output will be

	Fruits	Ranks
0	Mangoes	1
1	Apples	2
2	Bananas	3
3	Grapes	4
4	Oranges	5

Locate Row

From the result above, it is clear that the DataFrame is like a table with rows and columns.

Pandas uses the loc attribute to return one or more specified row(s).

Example 2: Return row 0.

Code

import pandas as pd

data = {

'Fruits': ["Mangoes", "Apples","Bananas", "Grapes", "Oranges"],

'Popularity Ranks': [1, 2, 3, 4, 5]

}

#load data into a DataFrame object:

df = pd.DataFrame(data)

print(df.loc[0])

the output will be

Fruits Mangoes

Popularity Ranks 1

Name: 0, dtype: object

.

Example 3: Return row 0 and 1.

Code

import pandas as pd

data = {

'Fruits': ["Mangoes", "Apples","Bananas", "Grapes", "Oranges"],

'Popularity Ranks': [1, 2, 3, 4, 5]

}

#load data into a DataFrame object:

df = pd.DataFrame(data)

print(df.loc[[0, 1]])

the output will be

Fruits Ranks

0 Mangoes 1

1 Apples 2

Note: When using [], the result is a Pandas DataFrame.

Named Indexes: With the index argument, you can name your own indexes.

Example 4: Add a list of names to give each row a name.

Code

import pandas as pd

data = {

"Movies": [1, 2, 3],

"Duration": [120, 150, 240]

}

df = pd.DataFrame(data, index = ["shark 1", "shark 2", "shark 3"])

print(df)

the output will be

Movies Duration

shark 1 1 120

shark 2 2 150

shark 3 3 240

Locate Named Indexes: Use the named index in the loc attribute to return the specified row(s).

Example 5: Return "shark3".

Code

import pandas as pd

data = {

"Movies": [1, 2, 3],

"Duration": [120, 150, 240]

}

df = pd.DataFrame(data,
index = ["shark 1", "shark 2", "shark 3"])

print(df.loc["shark 3"])

the output will be

Movies 3

Duration 240

Name: shark 3, dtype: int64

Load Files Into a DataFrame

If your data sets are stored in a file, Pandas can load them into a DataFrame.

Example 6: Load a comma separated file (CSV file) into a DataFrame.

Code

import pandas as pd

df = pd.read_csv('tennis.csv')

print(df)

the output will be